Activation of hypochlorite bleaching of dyes

ABSTRACT

A method of bleaching of certain triarylmethane dyes in aqueous systems with low concentration of hypochlorite ion, activated by the presence of bromide ion and ammonium ions. The method is particularly useful in providing a disappearing color signal in the automatic cleaning and sanitizing of toilet bowls with low concentrations of hypochlorite. Compositions and articles for implementing the practice of the method in the automatic cleaning and sanitizing of toilet bowls are also disclosed.

TECHNICAL FIELD

The present invention relates to the activation of the bleaching ofcertain triarylmethane dyes with low concentrations of hypochlorite,wherein the activator is a combination of ammonium ion and bromide ion.The invention is particularly useful in the automatic cleaning andsanitizing of flush toilets. The dye and a hypochlorite sanitizing agentare separately and simultaneously dispensed to the toilet bowl (withactivator) with each flush. The dye is bleached by the hypochlorite to acolorless state in the toilet bowl within a short time after flushing,thereby providing a visual signal of the activity of the hypochlorite.

BACKGROUND ART

This invention relates to the bleaching of certain triarylmethane dyesin solution with low concentrations of hypochlorite ion, activated bythe combination of bromide ion and ammonium ion. In particularlypreferred embodiments, the invention relates to methods, compositionsand articles for automatically cleaning and sanitizing toilets wherein adye/activator composition and hypochlorite are separately dispensed intothe toilet bowl during flushing. The water in the bowl at the end of theflush is colored by the dye. However, within a relatively short periodof time after the flush, the dye is oxidized to a colorless statethereby providing a visual signal that the hypochlorite sanitizing agentis present and "acting" in the bowl.

Automatically dispensed toilet bowl cleaning and/or sanitizing products,which contain dyes to provide a visual signal to the user that productis being dispensed, are well known. Such products are sold in the UnitedStates under the brand names VANISH AUTOMATIC (Drackett Products),TY-D-BOL AUTOMATIC (Knomark, Inc.) and SANIFLUSH AUTOMATIC(Boyle-Midway). None of these products contains a hypochloritesanitizing agent and all of them provide a color to the bowl water whichpersists between flushing. U.S. Pat. No. 3,504,384, Radley et al.,issued Apr. 7, 1970, discloses a dual compartment dispenser forautomatically dispensing a hypochlorite solution and a surfactant/dyesolution to the toilet bowl during flushing. The dye which is taught inthe patent is Disulfide Blue VN150. It is believed that the dye referredto in Radley et al. is actually Disulphine Blue VN150 (Color Index No.42045). (The abbreviation "C.I." will be used hereinafter to designate"Color Index.") This dye has been reported in U.S. Pat. No. 4,248,827,Kitko, issued Feb. 3, 1981 to be quite resistant to oxidation to acolorless state by hypochlorite; thus, it too provides a persistentcolor to the toilet bowl water, even in the presence of thehypochlorite.

A persistent color in the toilet bowl water has certain attendantnegatives. The dye can cause staining of the toilet bowl itself or ofdeposits (such as water hardness deposits) which accumulate on thesurfaces of the bowl between manual cleanings. Also, a persistentcolored solution in the bowl will tend to obscure medical symptoms suchas the passing of blood during excretion or urination. Further, apersistent color in the toilet bowl water tends to obscure otherwisevisible evidence of soiling on surfaces of the toilet bowl which arebelow the water line.

U.S. Pat. No. 4,248,827 supra discloses certain dyes which are bleachedto a colorless state in less than 10 minutes in the toilet bowl by lowconcentrations of hypochlorite or hypochlorite which is catalyzed bybromide ion. Among these is the triarylmethane dye Acid Green 2G (C.I.No. 42085). In this dye there are no substituents on the aryl rings inthe positions which are ortho to the ring carbon which is attached tothe methane carbon. U.S. Pat. No. 4,248,827 also discloses certaintriarylmethane dyes which are not bleached to a colorless state withinthe stated 10 minute period by hypochlorite or hypochlorite/bromide.These are FD and C Blue No. 1 (C.I. No. 42090), FD and C Green No. 3(C.I. No. 42053) and Disulphine Blue VN (C.I. No. 42045). All of thesetriarylmethane dyes have a substituent group in the ortho position onone of the aryl rings attached to the methane carbon.

An object of the present invention is to provide a method for bleachingaqueous solutions of triarylmethane dyes which have a substituent in theortho position of at least one of the aryl rings attached to the methanecarbon, with low concentrations of hypochlorite ion.

Another object of the invention is to provide a method for automaticcleaning and sanitization of toilets wherein a visual color signal isprovided to indicate that the sanitizing agent is present and acting inthe toilet bowl, and to provide articles and compositions adapted foruse in said method.

Another object of the invention is to provide a visual color signalwhich persists in the toilet bowl for a relatively short time afterflushing.

Another object of the invention is to provide, by a visual color signal,a means by which the consumer will know when a new supply of sanitizingagent needs to be provided for the toilet.

DISCLOSURE OF THE INVENTION

The present invention broadly relates to a method of bleachingwater-soluble triarylmethane dyes which have in their structure themoiety ##STR1## wherein X is selected from the group consisting ofsubstituent groups other than hydrogen or methyl and Y is selected fromthe group consisting of X, hydrogen and methyl, said method comprisingthe step of forming a solution comprising from about 0.02 to about 2 ppmof said dye, from about 2 to about 30 ppm of available chlorine fromhypochlorite ion, from about 0.1 to about 3 ppm bromide ion and fromabout 0.1 to about 2 ppm ammonium ion, the available chlorine to dyeratio in said solution being from about 2:1 to about 150:1, and the pHof said solution being from about 6 to about 9.5. (All compositions,concentrations and proportions herein are stated on a "by weight" basisunless indicated otherwise).

In a preferred aspect, the present invention relates to a method oftreating a flush toilet, which comprises a flush tank and bowl, with ahypochlorite sanitizing agent each time the toilet is flushed, andproviding a transitory visual signal to indicate the activity of thesanitizing agent in the bowl. The said method comprises the step ofdispensing from separate dispensing means, into the flush water; (A) anaqueous solution of a compound which produces hypochlorite ion inaqueous solution; and (B) an aqueous solution comprising atriarylmethane dye as described above, a compound which produces bromideion in aqueous solution and a compound which produces ammonium ion inaqueous solution, thereby to form a solution in the toilet bowl at theend of the flush cycle which comprises from about 0.02 to about 2 ppm ofsaid dye, from about 2 ppm to about 30 ppm available chlorine from saidhypochlorite ion, from about 0.1 ppm to about 3 ppm bromide ion, fromabout 0.1 ppm to about 2 ppm ammonium ion and an available chlorine todye ratio of from about 2:1 to about 150:1, said solution in said bowlhaving a pH of from about 6 to about 9.5, wherein said solution in saidbowl is bleached from a colored state to a colorless state within about40 minutes (preferably within about 20 minutes) after the end of saidflush cycle.

The bromide and ammonium ions function as "activators" which acceleratethe bleaching action of the hypochlorite on the dye.

The invention also comprises articles of manufacture and compositionsuseful in carrying out the method in a flush toilet.

Since the preferred aspect of the present invention relates to its usein the automatic cleaning and sanitizing of flush toilets, the inventionwill be described herein primarily in the context of that utility.

The term "water-soluble" as used herein means that the material inquestion has a solubility in ambient temperature water which issufficient to produce the concentrations specified for that material inthe hereindescribed invention.

The Sanitizing Agent

The sanitizing agent of the present invention can be any compound whichprovides the hypochlorite ion (OCl⁻) in aqueous solution. Such compoundsinclude alkali metal and alkaline earth metal hypochlorites,hypochlorite addition products, chloramines, chlorimines, chloramides,and chorimides. Specific examples of compounds of this type includesodium hypochlorite, potassium hypochlorite, lithium hypochlorite,calcium hypochlorite, calcium hypochlorite dihydrate, monobasic calciumhypochlorite, dibasic magnesium hypochlorite, chlorinated trisodiumphosphate dodecahydrate, potassium dichloroisocyanurate, sodiumdichloroisocyanurate, sodium dichloroisocyanurate dihydrate,1,3-dichloro-5,5-dimethylhydantoin, N-chlorosulfamide, Chloramine T,Dichloramine T, Chloramine B, Dichloramine B, and Di-Halo(bromochlorodimethyl hydantoin). A particularly preferred sanitizingagent composition suitable for use in the practice of the presentinvention is described in the commonly assigned U.S. Pat. No. 4,281,421,Nyquist et al., issued Aug. 4, 1981 and the commonly assigned U.S. Pat.No. 4,200,606, Kitko, issued Apr. 29, 1980, both of said patents beingincorporated herein by reference. The compositions described in saidapplications are compacted cakes comprising lithium hypochlorite andcalcium hypochlorite. The composition in the Nyquist et al. patentadditionally comprises sodium metasilicate.

By virtue of the strong oxidizing power of the hypochlorite ion, it ishighly effective in bleaching stains, breaking down and removing soilsand killing microorganisms, thereby providing effective santizing actionin the toilet bowl.

The amount of hypochlorite-providing sanitizing compound dispensed tothe toilet in the process of the invention can vary over a wire range,but preferably should be sufficient to provide from about 2 to about 30ppm (preferably from about 3 to about 8 ppm) available chlorine in thebowl water at the end of the flush. Only a very small amount of theavailable chlorine which is delivered to the bowl will be utilized indecolorizing the dye. The sanitizing agent can be formulated as anaqueous liquid if it is to be dispensed from a dispensing means designedto receive liquids. The sanitizing agent can also be formulated into theform of a solid cake for use in dispensing means which are designed toreceive a cake of solid material (see description of dispensing meansbelow). The level of available chlorine in the bowl water can bemeasured by well-known methods such as the DPD Ferrous TitrametricMethod or the Stabilized Neutral Orthotolidine Method, described,respectively, at pages 129 and 126 of Standard Methods for theExamination of Water and Wastewater, 13th Ed., published by AmericanPublic Health Association.

Dyes

The dyes of the present invention are water-soluble triarylmethane dyeswhich have in their formula the structural feature ##STR2## wherein X isa substituent other than hydrogen or methyl, and Y is a substituentselected from X, hydrogen and methyl. Y is preferably hydrogen. The Xsubstituent can be any of a wide variety of substituent groups. Theseinclude alkyls such as isopropyl, and tertiary butyl, halogens such aschlorine or bromine, sulfonate, phosphate, carboxylate, hydroxyl and thelike. For purposes of convenient description, these dyes will bereferred to herein as ortho-substituted triarylmethane dyes since theyall contain a substituent on at least one of the aryl rings in aposition ortho to the carbon attached to the methane carbon.

Examples of particular commercially available dyes which can be used inthe present invention are FD and C Green No. 3 (C.I. No. 42053), FD andC Blue No. 1 (C.I. No. 42090), Acid Green No. 9 (C.I. No. 42100) andHidacid Blue V Conc., which is the same structure as Disulphine Blue VN,both being designated by C.I. No. 42045. Preferred dyes herein are C.I.Nos. 42053, 42090 and 42100.

The molecular structures of these dyes are as follows: ##STR3##

When used to provide a colored-to-colorless color change signal in theautomatic cleaning and sanitizing of toilets in accordance with theinvention herein, the amount of dye dispensed to the toilet will dependon the color intensity desired, the amount of hypochlorite sanitizingagent dispensed into the toilet with the dye, and on the quickness withwhich it is desired to have the color disappear. Generally, the amountof dye dispensed will be sufficient to produce a dye concentration offrom about 0.02 to about 2 ppm, preferably from about 0.15 ppm to about1.0 ppm in the toilet bowl. Generally, the dye should be present in aratio of available chlorine:dye of from 2:1 to about 150:1, preferablyfrom about 5:1 to about 60:1. Dye concentrations and ratios herein arebased upon the amount of the actual dye compound, unless specifiedotherwise. Dyes are normally sold in the form of mixtures of dyecompound and inert diluent. For example, FD and C Blue No. 1, FD and CGreen No. 3, Acid Green No. 9 and Hidacid Blue V Conc. are believed tobe about 90% actual dye.

The following test data show the effect of the presence of ammonium ion,bromide ion and the combination of ammonium ion and bromide ion in thebleaching of dyes of the present invention with hypochlorite. The testwas conducted according to the following procedure at pH 6.5, 8 and 9,since this represents the typical range of pH's found in tap water.

One liter of distilled water at 70° F. is placed in a two liter beaker,and the water is kept in stirring motion witha magnetic stirrer. Theappropriate amount of sodium hypochlorite is added via a pipette to thewater from a 0.5% available chlorine aqueous stock solution of sodiumhypochlorite, so as to yield 5 ppm available chlorine in the testsolution. The pH is then adjusted to the desired level with a 1% aqueoussolution of NaOH or HCl, as needed. The appropriate amounts of sodiumbromide and ammonium chloride are added from 0.1% aqueous stocksolutions to provide the desired concentrations of these ions. The colorchange reaction is initiated by the addition of the appropriate amountof a stock solution of dye (0.1% dye, on an "as received" basis, inwater). The solution is then observed to determine the time fordisappearance of color.

The following tables present data on the testing of the fourabove-mentioned commercially available ortho-substituted triarylmethanedyes at a hypochlorite concentration of 5 ppm available chlorine. Theabsolute time values obtained in these discoloration tests are notnecessarily the same as will be experienced in actual dispensing ofdye/activator solution and hypochlorite solution into the toilet via theflush tank during flushing. Generally, the time values obtained in suchactual use situations are somewhat shorter. This is due to the fact thatwhen the respective concentrated solutions are dispensed into the flushwater during the flush they come into contact with each other beforebeing completely diluted to the concentration desired in the bowl.Contact between the hypochlorite, dye and activator ions before dilutionto the intended bowl water concentration results in a faster reactionrate during the short period in which such contact occurs. Nevertheless,the data in Tables 1-4 are consistent in demonstrating the enhancedbleaching effect obtained by combining ammonium and bromide ions asactivators for bleaching of the subject dyes.

                  TABLE 1                                                         ______________________________________                                        FD&C Blue No. 1 (0.45 ppm*)                                                                                 Time for                                                                      Color Dis-                                                                    appearance                                      pH    ppm Br.sup.-  ppm NH.sub.4.sup.+                                                                      (Minutes)                                       ______________________________________                                        6.5   0             0         >60                                             6.5   1             0         >60                                             6.5   0             0.225     22                                              6.5   1             0.225     10                                              8     0             0         >60                                             8     1             0         38                                              8     0             0.225     25                                              8     1             0.225     14                                              9     0             0         >60                                             9     1             0         >60                                             9     0             0.225     >60                                             9     1             0.225     25                                              ______________________________________                                         *0.5 ppm on "as received" basis                                          

                  TABLE 2                                                         ______________________________________                                        FD&C Green No. 3 (0.45 ppm*)                                                                                Time for                                                                      Color Dis-                                                                    appearance                                      pH    ppm Br.sup.-  ppm NH.sub.4.sup.+                                                                      (Minutes)                                       ______________________________________                                        6.5   0             0         >60                                             6.5   1             0         20                                              6.5   0             0.225     40                                              6.5   1             0.225     10                                              8     0             0         >60                                             8     1             0         28                                              8     0             0.225     30                                              8     1             0.225     4                                               9     0             0         >60                                             9     1             0         >60                                             9     0             0.225     >60                                             9     1             0.225     30                                              ______________________________________                                         *0.5 ppm on "as received" basis                                          

                  TABLE 3                                                         ______________________________________                                        Acid Green 9 (0.9 ppm*)                                                                                     Time for                                                                      Color Dis-                                                                    appearance                                      pH    ppm Br.sup.-  ppm NH.sub.4.sup.+                                                                      (Minutes)                                       ______________________________________                                        6.5   0             0         >60                                             6.5   1             0         21                                              6.5   0             0.225     >60                                             6.5   1             0.225     15                                              8     0             0         >60                                             8     1             0         29                                              8     0             0.225     >60                                             8     1             0.225     12                                              9     0             0         35                                              9     1             0         37                                              9     0             0.225     30                                              9     1             0.225     19                                              ______________________________________                                         *1 ppm on "as received" basis                                            

                  TABLE 4                                                         ______________________________________                                        Hidacid Blue V Conc. (0.45 ppm*)                                                                            Time for                                                                      Color Dis-                                                                    appearance                                      pH    ppm Br.sup.-  ppm NH.sub.4.sup.+                                                                      (Minutes)                                       ______________________________________                                        6.5   0             0         15                                              6.5   1             0         >60                                             6.5   0             0.225     20                                              6.5   1             0.225     7                                               8     0             0         >60                                             8     1             0         8                                               8     0             0.225     20                                              8     1             0.225     4                                               9     0             0         >60                                             9     1             0         35                                              9     0             0.225     >60                                             9     1             0.225     21                                              ______________________________________                                         *0.5 ppm on "as received" basis                                          

While not wishing to be bound by theory, it is believed that theortho-substituted triarylmethane dyes herein are resistant to bleachingby hypochlorite because of the steric and/or electrostatic effects ofthe substituents in the ortho position. It is believed that theactivator ions react with hypochlorite to form species which attack thedye at sites different from those at which hypochlorite attacks. Morespecifically, it is believed that with the activator species, the attackoccurs at double bond sites (electrophilic addition), rather than at thetriarylmethane carbon (nucleophilic addition).

Activator Ions

The activator system for carrying out the method of the presentinvention is the combination of ammonium ions and bromide ions. Theseions can be supplied by any water-soluble source of the ions. Forexample, bromide ion can be provided by water-soluble inorganic saltssuch as the alkali metal bromides (e.g., sodium and potassium bromides),alkaline earth metal bromides (e.g., calcium and magnesium bromides),zinc bromide and ferric bromide. Organic salts such as cetylpyridiniumbromide and cetyltrimethylammonium bromide can also be used. In thecontext of toilet bowl treatment, the alkali metal bromides and ammoniumbromide are preferred. Ammonium ions can be provided by inorganic saltssuch as ammonium chloride, ammonium sulfate, ammonium nitrate, ammoniumphosphate and ammonium fluoride, or organic salts such as ammoniumformate, ammonium citrate or ammonium acetate.

A preferred source of both ammonium and bromide ions is ammoniumbromide.

The amount of ammonium ion and bromide ion, respectively, which shouldbe present in solution to activate the bleaching of the otho-substitutedtriarylmethane dyes in the method of the invention can vary over a widerange. Generally there should be at least about 0.1 ppm of each ion.Preferably there should be from about 0.1 to about 3 ppm bromide ion and0.1 to 2 ppm ammonium ion, and most preferably from about 0.2 to about 1ppm of each ion.

When formulated into compositions suitable for use in the method hereinto separately provide hypochlorite and dye to the toilet bowl, thecompounds which provide the ammonium and bromide activator ions shouldbe formulated into the dye composition, rather than the hypochoritesanitizer composition.

Dye/Activator-Salt Compositions

The dyes and activator salts herein can be formulated into compositionsfor use in the method herein. Such compositions will normally comprisefrom about 0.2% to about 15% dye and an amount of activator saltssufficient to provide from about 0.5% to about 18% (preferably fromabout 2% to about 8%) bromide ion and from about 0.5% to about 11%(preferably from about 0.5% to about 1.5%) ammonium ion in thecomposition.

Optionally, these dye/activator-salt compositions can contain otheringredients which it is desired to dispense into the toilet bowl, suchas, for example, surfactants, sequestering agents and perfumes, as wellas diluents such as water, organic solvents such as ethanol, and organicor inorganic salts such as sodium sulfate, sodium chloride and sodiumacetate.

Surfactants can provide enhanced cleaning performance through breakupand emulsification of soils, and also provide some sudsing in the toiletbowl, which may be aesthetically desirable. Perfumes provide a pleasantsmell to the area surrounding the toilet and also help to obscure the"bleach" smell of the sanitizing agent. Sequestrants aid soil removal bysequestration of multivalent metal ions.

When the dyes and activator-salts herein are formulated withsurfactants, the resulting compositions will generally comprise fromabout 5% to about 95% surfactant. Perfumes will normally be used atlevels of up to about 25% and inert diluents at levels up to about 90%.Sequestering agents such as potassium pyrophosphate, sodiumtripolyphosphate and ethylenediamine pentaacetate can be used at levelsup to about 25%.

Certain particularly desirable sequestering agents which prevent theformation of stains on toilet bowl surfaces caused byhypochlorite-oxidation of manganese ions which may be present in thewater supply are the partially hydrolyzed polyacrylate polymers andethylene-maleic anhydride polymers described in the following commonlyassigned patents and application: U.S. Pat. No. 4,302,350, Callicott,issued Nov. 24, 1981; U.S. Ser. No. 028,613, Callicott, filed Apr. 9,1979, now abandoned; and U.S. Pat. No. 4,283,300, Kurtz, issued Aug. 11,1981, all incorporated herein by reference. Examples of suitablepartially hydrolyzed polyacrylamide polymers which are commerciallyavailable are P-35 and P-70 from American Cyanamid Company and examplesof suitable commercially available ethylene-maleic anhydride polymersare EMA-21 and EMA-31 from Monsanto Company.

Compositions comprising the dye, activator salts and a surfactant and/orother ingredients can be conveniently formed into a cake for use indispensers which are designed to receive a cake of solid material (seedescription of dispensing means, below). Such cakes can be made byextrusion or hydraulic stamping, or by pouring a melt of the compositioninto a mold and solidifying the composition by cooling.

If it is desired to use a dispensing means which is designed to receiveliquids, the dye, activator salts and any optional ingredients such assurfactants, etc., can be formulated into liquid compositions.

Surfactants suitable for use in the compositions herein can be of theanionic, nonionic, ampholytic or zwitterionic type.

Anionic surfactants operable in compositions suitable for use inpracticing the present invention can be broadly described as thewater-soluble salts, particularly the alkali metal salts, of organicsulfuric acid reaction products having in their molecular structure analkyl or alkaryl radical containing from about 8 to about 22 carbonatoms and a radical selected from the group consisting of sulfonic acidand sulfuric acid ester radicals. (Included in the term alkyl is thealkyl portion of higher acyl radicals.) Important examples of theanionic surfactants which can be employed in the practicing of thepresent invention are the sodium or potassium alkyl sulfates, especiallythose obtained by sulfating the higher alcohols (C₈ -C₁₈ carbon atoms)produced by reducing the glycerides of tallow or coconut oil; sodium orpotassium alkyl benzene sulfonates, in which the alkyl group containsfrom about 9 to about 15 carbon atoms, (the alkyl radical can be astraight or branched aliphatic chain); paraffin sulfonate surfactantshaving the general formula RSO₃ M, wherein R is a primary or secondaryalkyl group containing from about 8 to about 22 carbon atoms (preferably10 to 18 carbon atoms) and M is an alkali metal, e.g., sodium orpotassium; sodium alkyl glyceryl ether sulfonates, especially thoseethers of the higher alcohols derived from tallow and coconut oil;sodium coconut oil fatty acid monoglyceride sulfates and sulfonates;sodium or potassium salts of sulfuric acid esters of the reactionproduct of one mole of a higher fatty alcohol (e.g., tallow or coconutoil alcohols) and about 1 to 10 moles of ethylene oxide; sodium orpotassium salts of alkyl phenol ethylene oxide ether sulfates with about1 to about 10 units of ethylene oxide per molecule and in which thealkyl radicals contain from about 8 to about 12 carbon atoms; thereaction products of fatty acids esterified with isethionic acid andneutralized with sodium hydroxide where, for example, the fatty acidsare derived from coconut oil; sodium or potassium salts of fatty acidamides of a methyl tauride in which the fatty acids, for example, arederived from coconut oil and sodium or potassium β-acetoxy- orβ-acetamido-alkane-sulfonates where the alkane has from 8 to 22 carbonatoms.

Nonionic surfactants which can be used in practicing the presentinvention can be of three basic types: the alkylene oxide condensates,the amides and the semipolar nonionics.

The alkylene oxide condensates are broadly defined as compounds producedby the condensation of alkylene oxide groups (hydrophilic in nature)with an organic hydrophobic compound, which can be aliphatic or alkylaromatic in nature. The length of the hydrophilic or polyoxyalkyleneradical which is condensed with any particular hydrophobic group can bereadily adjusted to yield a water-soluble-compound having the desireddegree of balance between hydrophilic and hydrophobic elements.

Examples of such alkylene oxide condensates include:

1. The condensation products of aliphatic alcohols with ethylene oxide.The alkyl chain of the aliphatic alcohol can either be straight orbranched and generally contains from about 8 to about 22 carbon atoms.Examples of such ethoxylated alcohols include the condensation productof about 6 moles of ethylene oxide with 1 mole of tridecanol, myristylalcohol condensed with about 10 moles of ethylene oxide per mole ofmyristyl alcohol, the condensation product of ethylene oxide withcoconut fatty alcohol wherein the coconut alcohol is a mixture of fattyalcohols with alkyl chains varying from 10 to 14 carbon atoms andwherein the condensate contains about 6 moles of ethylene oxide per moleof alcohol, and the condensation product of about 9 moles of ethyleneoxide with the above-described coconut alcohol. Examples of commerciallyavailable nonionic surfactants of this type include Tergitol 15-S-9marketed by the Union Carbide Corporation, Neodol 23-6.5 marketed by theShell Chemical Company and Kyro EOB marketed by The Procter and GambleCompany.

2. The polyethylene oxide condensates of alkyl phenols. These compoundsinclude the condensation products of alkyl phenols having an alkyl groupcontaining from about 6 to about 12 carbon atoms in either a straightchain or branched chain configuration, with ethylene oxide, the saidethylene oxide being present in amounts equal to 5 to 25 moles ofethylene oxide per mole of alkyl phenol. The alkyl substituent in suchcompounds can be derived, for example, from polymerized propylene,diisobutylene, octene, or nonene. Examples of compounds of this typeinclude nonyl phenol condensed with about 9.5 moles of ethylene oxideper mole of nonyl phenol, dodecyl phenol condensed with about 12 molesof ethylene oxide per mole of phenol, dinonyl phenol condensed withabout 15 moles of ethylene oxide per mole of phenol, di-isooctylphenolcondensed with about 15 moles of ethylene oxide per mole of phenol.Commercially available nonionic surfactants of this type include IgepalCO-610 marketed by the GAF Corporation; and Triton X-45, X-114, X-110and X-102, all marketed by the Rohm and Haas Company.

3. The condensation products of ethylene oxide with a hydrophobic baseformed by the condensation of propylene oxide with propylene glycol. Thehydrophobic portion of these compounds has a molecular weight of fromabout 1500 to 1800 and of course exhibits water insolubility. Theaddition of polyoxyethylene moieties of this hydrophobic portion tendsto increase the water-solubility of the molecule. Examples of compoundsof this type include certain of the commercially available Pluronicsurfactants marketed by the Wyandotte Chemicals Corporation.

4. The condensation products of ethylene oxide with the productresulting from the reaction of propylene oxide and ethylene diamine. Thehydrophobic base of these products consists of the reaction product ofethylene diamine and excess propylene oxide, said base having amolecular weight of from about 2500 to about 3000. This base iscondensed with ethylene oxide to the extent that the condensationproduct contains from about 40% to about 80% by weight ofpolyoxyethylene and has a molecular weight of from about 5,000 to about11,000. Examples of this type of nonionic surfactant include certain ofthe commercially available Tetronic compounds marketed by the WyandotteChemicals Corporation.

Examples of the amide type of nonionic surfactants include the ammonia,monoethanol and diethanol amides of fatty acids having an acyl moiety offrom about 8 to about 18 carbon atoms. These acyl moieties are normallyderived from naturally occurring glycerides, e.g., coconut oil, palmoil, soybean oil and tallow, but can be derived synthetically, e.g., bythe oxidation of petroleum, or by hydrogenation of carbon monoxide bythe Fischer-Tropsch process.

Examples of the semi-polar type of nonionic surfactants are the amineoxides, phosphine oxides and sulfoxides. These materials are describedmore fully in U.S. Pat. No. 3,819,528, Berry, issued June 25, 1974, andincorporated herein by reference.

Ampholytic surfactants which can be used in practicing the presentinvention can be broadly described as derivatives of aliphatic amineswhich contain a long chain of about 8 to about 18 carbon atoms and ananionic water-solubilizing group, e.g., carboxy, sulfo and sulfato.Examples of compounds falling within this devinition aresodium-3-dodecylamino-propionate, sodium-3-dodecylamino propanesulfonate, and dodecyl dimethylammonium hexanoate.

Zwitterionic surfactants which can be used in practicing the presentinvention are broadly described as internally-neutralized derivatives ofaliphatic quaternary ammonium and phosphonium and tertiary sufoniumcompounds, in which the aliphatic radical can be straight chain orbranched, and wherein one of the aliphatic substituents contains fromabout 8 to about 18 carbon atoms and one contains an anionicwater-solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, orphosphono.

Bleach-stable (i.e., hypochlorite-stable) surfactants which areespecially resistant to oxidation are the alkyl sulfates and paraffinsulfonates. Alkyl sulfates are the water-soluble salts of sulfated fattyalcohols containing from about 8 to about 18 carbon atoms in the alkylgroup. Examples of suitable alcohols which can be employed in alkylsulfate manufacture include decyl, lauryl, myristyl, palmityl andstearyl alcohols and the mixtures of fatty alcohols derived by reducingthe glycerides of tallow and coconut oil.

Specific examples of alkyl sulfate salts which can be employed in theinstant surfactant/dye compositions include sodium lauryl alkyl sulfate,sodium stearyl alkyl sulfate, sodium palmityl alkyl sulfate, sodiumdecyl sulfate, sodium myristyl alkyl sulfate, potassium lauryl alkylsulfate, potassium stearyl alkyl sulfate, potassium decyl sulfate,potassium palmityl alkyl sulfate, potassium myristyl alkyl sulfate,sodium dodecyl sulfate, potassium dodecyl sulfate, potassium tallowalkyl sulfate, sodium tallow alkyl sulfate, sodium coconut alkyl sulfatepotassium coconut alkyl sulfate and mixtures of these surfactants.Highly preferred alkyl sulfates are sodium coconut alkyl sulfate,potassium coconut alkyl sulfate, potassium lauryl alkyl sulfate andsodium lauryl alkyl sulfate.

Paraffin sulfonate surfactants have the general formula RSO₃ M, whereinR is a primary or secondary alkyl group containing from about 8 to about22 carbon atoms (preferably 10 to 18 carbon atoms) and M is an alkalimetal, e.g., sodium or potassium. Paraffin sulfonate surfactants andmethods for their preparation are well known in the art. They may beprepared, for example, by reaction of hydrocarbons with sulfur dioxide,oxygen and a sulfonation reaction initiator. Alternatively, they may beprepared by reacting an alkene and a sodium bisulfite under suitableradiation or catalysis, as disclosed in British Pat. No. 1,451,228published Sept. 29, 1976, and hereby incorporated herein by reference.Paraffin sulfonate surfactants are commercially available, e.g., fromFarbwerke Hoechst A. G.

Preferred paraffin sulfonates herein are secondary paraffin sulfonates.Examples of specific paraffin sulfonates herein are:

Sodium-1-decane sulfonate;

Potassium-2-decane sulfonate;

Lithium-1-dodecane sulfonate;

Sodium-6-tridecane sulfonate;

Sodium-2-tetradecane sulfonate;

Sodium-1-hexadecane sulfonate;

Sodium-4-octadecane sulfonate;

Sodium-3-octadecane sulfonate.

Normally, the paraffin sulfonates are available as mixtures ofindividual chain lengths and position isomers, and such mixtures aresuitable for use herein.

Naphthalene sulfonate surfactants are also suitable for use in thecompositions herein. These are described in detail in U.S. Pat. No.4,278,571, Choy, issued July 14, 1981, incorporated by reference herein.Exemplary naphthalene sulfonate surfactants are Petro BAF and Petro 22from Petrochemicals Company, Inc.

Another optional ingredient which can be included in thedye/activator-salt compositions herein is an organic solubility controlagent for the surfactant, if surfactant is used. Such agents aredescribed in U.S. Pat. No. 4,246,129, Kacher, issued Jan. 20, 1981,incorporated herein be reference. An exemplary solubility control agentis isobornyl acetate. Such agents can be present in the compositionsherein at levels of from about 0.5% to about 20%.

Another optional ingredient which can be included in thedye/activator-salt compositions herein is a poly(ethylene oxide) resinsuch as described in the copending, commonly assigned application ofClement K. Choy and Robert A. Greene, U.S. Ser. No. 153,993, filed May28, 1980, incorporated by reference herein. These resins reduce theaerosolization of water from the toilet bowl during flushing. Anexemplary poly(ethylene oxide) resin is Polyox C from Union CarbideCompany.

If needed, pH adjusting agents such as sodium carbonate, sodiumsilicate, oxalic acid, citric acid, etc., can be incorporated into thedye/activator-salt composition. Normally, however, such agents are notneeded since the flush water will already be within the desired pHrange.

Dispensing Means

In order to provide automatic sanitizing of the toilet bowl inaccordance with the present invention, it is essential that thehypochlorite sanitizing agent, the dye and the ammonium and bromideactivator ions, in the form of relatively concentrated solutions, bedispensed into the flush water each time the toilet is flushed.

It is within the contemplation of the present invention that theconcentrated solution of one of the components (i.e., either thedye-activator composition or the sanitizing agent composition) bedispensed into the flush tank during the refill after a flush (therebyforming a dilute solution of one composition in the flush water which isstored in the tank between flushes) and that the concentrated solutionof the other composition be dispensed into this treated flush waterduring the "down-flush," i.e., during the time the flush water isflowing from the tank to the bowl during the next succeding flush.Dispensing means which operate to dispense solutions into a toilet tankduring the time it is refilling are described, for example, in U.S. Pat.Nos. 1,798,090, Lebegue, issued Mar. 24, 1931; 3,339,801, Hronas, issuedSept. 5, 1967; and 3,121,236, Yadro et al., issued Feb. 18, 1964.

It is preferred that both of the concentrated solutions be dispensedinto the flush water on the down-flush, i.e., that they be dispensedinto the flush water during the time the flush water is flowing from thetank into the bowl. In this preferred mode of operation, it isadditionally preferred that the dispensing of the hypochlorite and dyeplus activator ions should occur near the end of the flush in order toavoid wastage of dye and hypochlorite and to keep to a minimum the timeof contact between dye, hypochlorite and activator ions before theyenter the bowl. The respective dispensing means for the hypochlorite anddye/activator solutions should preferably be in positions relative toeach other in the toilet tank so that these concentrated solutions willbe diluted by flush water during the flush before they come into contactwith each other, i.e., intimate mixture of streams of the twoconcentrated solutions in the flush tank should preferably be avoided.

Dispensing means for automatically dispensing solutions of chemicalsinto the flush water during the down-flush are well known to the art.U.S. Pat. No. 3,504,384, Radley et al., issued Apr. 7, 1970, discloses adual dispenser for separately dispensing a detergent/dye solution and ahypochlorite solution into the flush water during the flush. Water fromthe flush tank flows into the respective dispenser chambers as the tankfills after a flush, where it comes into contact with a soliddetergent/dye composition and a solid hypochlorite-producing compositionin the respective chambers. During the interval between flushes,relatively concentrated solutions of the hypochlorite and detergent/dyecompositions form in the respective chambers, and these solutions aredischarged into the flush water on the next flush. It should be notedthat the inlet and outlet ports of the dispenser chambers in the Radleyet al. dual dispenser are not closed between flushings, and thereforethere is opportunity for ingredients in the respective concentratedsolutions in the chambers to diffuse into the tank water betweenflushes, whereby there is also opportunity for ingredients from onedispenser chamber to ultimately find their way into the solution in theother dispenser chamber. The longer the time interval between flushes,the more likelihood there is that some portion of the contents of thetwo dispenser chambers will have an opportunity to come into contactwith each other before they are dispensed into the flush water on thenext flush. While dispensing devices of the type disclosed in Radley etal. can be used in the method of the present invention, they are notpreferred. Because of the high reactivity between the dye and theactivated hypochlorite, the color intensity and duration of the colorsignal in the bowl will be less reproducible from one flush to the nextthan if the dye/activator composition and hypochlorite composition aresubstantially completely isolated from the tank water (and, therefore,from each other) between flushes. This isolation can be accomplished inthe dispensing means by providing a blocking means such as an air bubbleor a mechanical seal which, during the period between flushes, blocksthe ports by which liquid flows into and out of the dispensing means.Depending on the type dispensing means used, and the materials used inconstructing it, complete isolation of the concentrated solutions fromthe tank water may not always be possible since some small amount ofsolution may escape by capillary action, imperfect sealing of the inletand outlet ports, etc. In any event, the greater the extent of isolationwhich can be obtained, the better.

Dispensers which completely or substantially completely isolate theircontents from the tank water during the quiescent period between flushesare known to the art and are the preferred type for use in the presentinvention. Such dispensers are disclosed, for example, in U.S. Pat. No.3,831,205, issued Aug. 27, 1974, to Foley; U.S. Pat. No. 3,341,074,issued Sept. 12, 1967, to Panutti; U.S. Pat. No. 4,036,407, issued July19, 1977, to Slone; U.S. Pat. No. 4,171,546, issued Oct. 23, 1979, toDirksing; U.S. Pat. No. 4,208,747, issued June 24, 1980, to Dirksing;and U.S. application Ser. No. 153,997, Choy, entitled PASSIVE DOSINGDISPENSER EXHIBITING IMPROVED RESISTANCE TO CLOGGING, filed May 28,1980. All of the foregoing patents and applications are incorporatedherein by reference.

Preferably, the amount of sanitizing composition placed in thesanitizing composition dispensing means should be chosen so as to lastat least as long as (i.e., through at least as many flushes as) theamount of dye/activator composition in the dye/activator compositiondispensing means. When the consumer no longer sees any color appear inthe bowl when flushing the toilet, this indicates that it is time toreplace the system (dye/activator and sanitizer). Conversely, if theconsumer sees that color persists in the toilet bowl, this is also anindication that the supply of sanitizing agent has been exhausted andthe system should be replaced. As indicated previously, it is lessdesirable to have a persistent color in the toilet bowl between flushes,and, therefore, it is preferable that the supply of sanitizer last forat least as long as the supply of dye/activator.

The dye plus activator and the sanitizing agents can be formulated intothe form of liquid or solid compositions for use in the toiletsanitizing method herein. The form of the composition will depend uponthe type of dispenser used. The most preferred dispensers are thosewhich are designed to receive a solid composition. With this type ofdispenser, water from the flush tank enters into the dispenser duringthe refill of the flush tank at the end of the flush. Water within thedispenser remains in contact with the solid composition between flushes,thereby forming a concentrated solution within the dispenser. When thetoilet is flushed, a predetermined amount of the concentrated solutionis discharged into the flush water as it flows from the tank to thebowl. Particularly preferred dispensers which are designed to receive asolid composition are those of the type disclosed in U.S. Pat. No.4,171,546 and 4,208,747, supra. These dispensers also isolate thecontents of the dispenser from the tank water during the quiescentperiod between flushes. In a preferred embodiment two dispensing meansare constructed into a dual dispenser unit, one dispensing meanscontaining the sanitizing agent composition and the other containing thedye/activator-salt composition. The two dispensing means in the dualdispenser unit can be of the same design or a different design from eachother.

Accordingly, the present invention also encompasses an article ofmanufacture designed for placement below the high water line of theflush tank of a toilet comprising a flush tank and a bowl, said articlecomprising two dispensing means (i.e., dispensers), the first dispensingmeans containing a solid composition which is soluble in water andcomprises a compound which provides hypochlorite ions in aqueoussolution, and a second dispensing means containing a solid compositionwhich is soluble in water and which contains an ortho-substitutedtriarylmethane dye (of the type hereinbefore set forth), a water-solublesource of bromide ion and a water-soluble source of ammonium ion, saidfirst dispensing means and second dispensing means each having means forreceiving water from the flush tank when said flush tank refills after aflush and for maintaining said received water in contact with therespective solid compositions in said first and second dispensing meansduring the quiescent period between flushes so as to form concentratedsolutions of said compositions in said respective dispensing meansbetween flushes, said first dispensing means and said second dispensingmeans each having means for releasing said concentrated solutions intothe water in the flush tank when said water flows from the tank duringflushing. When this article is placed in the flush tank of a toilet itis positioned in a manner such that the means for receiving water andthe means for releasing concentrated solutions in both of the respectivedispensing means are below the high water line of the flush tank. Thefirst and second dispensing means function to produce a concentration ofavailable chlorine from said hypochlorite of from about 2 ppm to about30 ppm, a concentration of dye of from about 0.02 ppm to about 2 ppm, aratio of available chlorine to dye of from about 2:1 to 150:1, aconcentration of bromide ion of at least 0.1 ppm, a concentration ofammonium ion of at least 0.1 ppm and a pH of from about 6 to about 9.5in the toilet bowl at the end of the flush. The color produced by saiddye in the water in the toilet bowl disappears within about 40 minutesafter the flush is completed. As indicated above, it is preferable thatthe respective dispensing means contain means for isolating theconcentrated solutions of the respective compositions from the tankwater during the quiescent periods between flushes.

The present invention will be illustrated by the following example.

EXAMPLE 1

This example illustrates the use of the present invention to provide adisappearing color signal in the automatic cleaning and sanitizing ofthe bowl of a flush toilet.

Sanitizer cakes for use in the present invention were prepared in thefollowing manner.

A blend of HTH (70% calcium hypochlorite) from Olin Corp., NiagaraFalls, N.Y.; Form 2 (35% lithium hypochlorite) from Lithium Corporationof America, Bessemer City, N.C.; sodium chloride; and Metzo Beads 2048sodium metasilicate from Philadelphia Quartz Co. of Philadephia, Pa.,was dry mixed in a Day-Nauta mixer for 20 minutes and stamped into a 3.0inch×1.67 inch×0.75 inch rectangular cake on a Stokes Model R-4 press ata force between 3.2 and 4.8 tons per square inch. The cake had thefollowing composition and weighed approximately 100 grams.

    ______________________________________                                        Ingredient      Wt. %                                                         ______________________________________                                        HTH             56                                                            Form 2          15                                                            NaCl            21.9                                                          Na metasilicate 7.1                                                           Total           100.0                                                         ______________________________________                                    

Dye/activator-salt cakes for use in the present invention were preparedin the following manner.

A co-flaked mixture was first produced by mixing together Hostapur SAS60 brand sodium paraffin sulfonate (approximately 84% active) fromAmerican Hoechst Co., Sommerville, N.J.; sodium chloride and 40% aqueoussolution of neutralized polyacrylamide resin (P-35 from Monsanto Co.,St. Louis, Mo.) in a steam heated mix tank with water to form a pastehaving a 60% solids content. The 40% aqueous solution of polyacrylamideresin was prepared by dissolving the resin in water and neutralizing toa pH (1% solution basis) of 5.0 to 5.5 with sulfuric acid. The paste ofparaffin sulfonate, salt and resin was then heated to 150° F..sup.± 10°F. and converted to flake form by drying to a moisture level of 1-2% ona drum dryer at 320° F.

The dried Hostapur/P-35/salt flakes were blended with ammonium bromide,FD&C Blue No. 1 dye and Hostapur SAS 60 flakes (made by drum dryingHostapur SAS 60, as received, to a moisture level of 1-2%), and theblend was dry-mixed in a double-arm Sigma-type mixer for 2-3 minutes.The perfume was then added, followed by 15 minutes of additional mixing.The resultant moist mixture was then plodded twice, once through aperforated plate and finally through a nozzle to form a log which wascut into cakes of approximately 65 grams having dimensions ofapproximately 3.34 inch×0.6 inch×1.94 inch. The cakes were dusted withtalc. These cakes had the following composition:

    ______________________________________                                        Ingredient            Wt. %                                                   ______________________________________                                        Hostapur SAS 60           68.73                                               P-35 resin    Co-flaked Mixture                                                                         11.30                                               NaCl                      1.00                                                Hostapur SAS 60 flakes                                                                              3.44                                                    Ammonium bromide      5.10                                                    Pine Cone perfume     9.00                                                    FD&C Blue No. 1       1.43                                                    Total                 100.00                                                  ______________________________________                                    

The above-described sanitizer cake and dye/activator-salt cake weresealed, respectively, into separate dispensers of a dual dispensingapparatus which was thermoformed from 0.022 inch thick polyvinylchloride, and which is suitable for automatic, simultaneous dispensingof sanitizer solution and dye/activator-salt solution into a flushingtoilet at each flush. Each of the dispensers in the dual dispensingapparatus was of a configuration generally similar to that described inFIG. 17 of U.S. Pat. No. 4,208,747, Dirksing, issued June 24, 1980.These separate dispensers (actually two separate dispensing means) ofthe dual dispensing apparatus produce concentrated solutions,respectively, of the sanitizer composition and the dye/activator-saltcomposition in water which enters the dispensers when the toilet tank isfilling after a flush. The respective dispensing means serve tosubstantially isolate the concentrated solutions from each other andfrom the tank water during the period between flushes, although a verysmall amount of dye solution was found to migrate into the flush tankbetween flushes. The positioning of the respective dispensing means ofthe dual dispensing apparatus is such as to minimize mixing of thedispensed sanitizer and dye/activator-salt solutions during the flushuntil they have been diluted with flush water. The measuring cavity andinlet conduit of the sanitizer-containing portion of the dual dispensingapparatus is so sized that approximately 7 cubic centimeters ofsanitizer-containing solution is dispensed with each flush cycle of thetoilet.

The dye/activator-salt containing portion of the dual dispensingapparatus is so sized that approximately five cubic centimeters ofdye/activator-salt containing solution is dispensed into the flush wateras it leaves the tank during each flush cycle of the toilet.

The aforedescribed exemplary embodiment of a dual dispensing apparatusfor carrying out the method of the present invention provides anexcellent release of both the sanitizer-containing solution and thedye/activator-salt containing solution throughout the life of the unit.

An American Standard Cadet toilet comprising a flush tank and a bowl wasequipped with this dispensing apparatus by mounting the apparatus in thetank with a mounting device of the type described in U.S. Pat. No.4,247,070, Dirksing, issued Jan. 27, 1981, incorporated by referenceherein. One hour prior to mounting the apparatus in the toilet tank,water was introduced into the respective dispensers. The pH of the tankwater was adjusted with either NaOH or HCl so as to give the desired pHin the toilet bowl after flushing. The temperature of the tank water was70° F. The toilet was then flushed and the time elapsed from thebeginning of the flush to the point at which the color disappeared fromthe bowl water was recorded. The available chlorine level in the bowlwater was determined at the end of the flush, using Water Chex, aproduct of The Medical-Surgical Division of Parke, Davis & Co. Also, thepH of the bowl water at the end of the flush was determined with a pHmeter. Results are set forth in Table 5.

                  TABLE 5                                                         ______________________________________                                                                      Disappearance                                   Tank H.sub.2 O                                                                        Bowl H.sub.2 O                                                                            Bowl H.sub.2 O                                                                          of Color in Bowl                                pH      pH          Av.Cl.sub.2                                                                             (Minutes)                                       ______________________________________                                        4.25    6.76        8         9                                               4.05    6.85        8         5                                               6.58    7.78        9         4                                               6.73    7.90        9          21/4                                           7.48    8.29        9          11/2                                           6.97    8.30        4         1                                               9.93    9.09        8          53/4                                           10.11   9.19        9          51/2                                           ______________________________________                                    

In the above experiment the sanitizer cake can be replaced with asanitizer cake consisting of 80% HTH calcium hypochlorite, 9% Form 2lithium hypochlorite and 11% sodium chloride, and similar colordisappearance results will be obtained.

What is claimed is:
 1. A method of treating a flush toilet, whichcomprises a flush tank and bowl, with a hypochlorite sanitizing agenteach time the toilet is flushed, and providing a transitory visualsignal to indicate the activity of the sanitizing agent in the bowl, thesaid method comprising the step of dispensing from separate dispensingmeans, into the flush water; (A) an aqueous solution of a compound whichproduces hypochlorite ion in aqueous solution; and (B) an aqueoussolution comprising a dye, a compound which produces bromide ion inaqueous solution and a compound which produces ammonium ion in aqueoussolution, thereby to form a solution in the toilet bowl at the end ofthe flush cycle which comprises from about 0.02 to about 0.45 ppm ofsaid dye, from about 2 ppm to about 30 ppm available chlorine from saidhypochlorite ion, from about 0.1 ppm to about 3 ppm bromide ion, fromabout 0.1 ppm to about 2 ppm ammonium ion and an available chlorine todye ratio of from about 2:1 to about 150:1, said solution in said bowlhaving a pH of from about 6 to about 9.5, wherein said dye is selectedfrom the group consisting of water-soluble, ortho-substitutedtriarylmethane dyes having in their structure the moiety ##STR4##wherein X is selected from the group consisting of substituent groupsother than hydrogen or methyl and Y is selected from the groupconsisting of X, hydrogen and methyl, and wherein said solution in saidbowl is bleached from a colored state to a colorless state within about40 minutes after the end of said flush cycle.
 2. The method of claim 1wherein the respective solutions (A) and (B), are both dispensed intothe flush water during the down-flush.
 3. The method of claim 2 whereinthe respective solutions (A) and (B), are substantially completelyisolated from the flush water in the toilet tank during the quiescentperiod between flushes of the toilet.
 4. The method of claim 3 whereinthe substituent X in the triarylmethane dye is selected from the groupconsisting of halogen, sulfonate, carboxylate, phosphate and hydroxyland wherein Y is hydrogen.
 5. The method of claim 4 wherein theconcentration of available chlorine is from about 3 ppm to about 8 ppmand the weight ratio of available chlorine to dye is from about 5:1 toabout 60:1.
 6. The method of claim 5 wherein the concentration ofbromide ion is from about 0.1 to about 3 ppm and the concentration ofammonium ion is from about 0.1 to about 2 ppm.
 7. The method of claim 6wherein the dye is selected from the group consisting of those havingColor Index Number designations 42053, 42090, 42045 and
 42100. 8. Themethod of claim 7 wherein the dye is selected from the group consistingof those designated by Color Index Numbers 42090, 42053 and 42100, theconcentration of bromide ion is from about 0.2 ppm to about 1 ppm andthe concentration of ammonium ion is from about 0.2 to about 1 ppm. 9.An article of manufacture designed for placement below the high waterline of the flush tank of a toilet comprising a flush tank and a bowl,said article comprising two dispensing means;(A) the first dispensingmeans containing a solid composition which is soluble in water andcomprises a compound which provides hypochlorite ions in aqueoussolution, and (B) a second dispensing means containing a water-solublesource of bromide ion, a water-soluble source of ammonium ion and a dyeselected from the group consisting of water-soluble, ortho-substitutedtriarylmethane dyes which have in their structure the moiety ##STR5##wherein X is selected from the group consisting of substituent groupsother than hydrogen or methyl and Y is selected from the groupconsisting of X, hydrogen and methyl, said first dispensing means andsecond dispensing means each having means for receiving water from theflush tank when said flush tank refills after a flush, and formaintaining said received water in contact with the respective solidcompositions in said first and second dispensing means during thequiescent period between flushes so as to form concentrated solutions ofsaid compositions in said respective dispensing means between flushes,said first dispensing means and said second dispensing means each havingmeans for releasing said concentrated solutions into the water in theflush tank when said water flows from the tank during flushing, saidfirst and second dispensing means and the compositions thereincooperating to produce, in the toilet bowl at the end of the flush, aconcentration of available chlorine of from about 2 ppm to about 30 ppm,a concentration of said dye of from about 0.02 ppm to about 0.45 ppmwith a ratio of available chlorine to dye of from about 2:1 to about150:1, a concentration of bromide ion of greater than 0.1 ppm, aconcentration of ammonium ion of greater than 0.1 ppm and a pH of fromabout 6 to about 9.5.
 10. The article of claim 9 wherein said firstdispensing means and second dispensing means each have means forretaining the said concentrated solutions in substantial isolation fromeach other and from the body of water in the flush tank during thequiescent period between flushes.
 11. The article of claim 10 whereinthe substituent X in the dye is selected from the group consisting ofhalogen, sulfonate, carboxylate, phosphate, and hydroxyl and whereinsubstituent Y is hydrogen.
 12. The article of claim 11 wherein therespective dispensing means and compositions are designed to cooperateso as to produce a concentration of available chlorine in the toiletbowl at the end of the flush of from about 3 ppm to about 8 ppm, aweight ratio of available chlorine to dye of from about 5:1 to about60:1, a bromide ion concentration of from about 0.1 to about 3 ppm andan ammonium ion concentration of from about 0.1 to about 2 ppm.
 13. Thearticle of claim 12 wherein the dye is selected from the groupconsisting of those having Color Index Number designations 42053, 42090,42045 and
 42100. 14. The article of claim 13 wherein the dye is selectedfrom the group consisting of those designated by Color Index Numbers42090, 42053 and 42100, the concentration of bromide ion is from about0.2 to about 1 ppm and the concentration of ammonium ion is from about0.2 to about 1 ppm.